Propeller



UNITED STATES PATENT OFFICE.

DANIEL HUGHES, OF ROCHESTER, NEW YORK.

PROPELLER.

Specification of Letters Patent No. 26,106, dated November 15` 12359.l

r['o all whom it may concern:

Be it known that I, DANlnL HUGHES, of

Rochester, in the county of Monroe and State of New York, have inventedanew and useful Propeller for Ships, Vessels, &c.; and I do herebydeclare that` the following is a full, clear, and exact description ofthe same, reference being had to the annexed drawings, making a part ofthis specification, in which- Figure l, represents an end view of avessel with my propeller, looking at the same from the stern. Fig. 2, isa horizontal section of do.

Similar letters of reference indicate corresponding parts in the twofigures.

This invention consists in arranging at the stern of the same vessel andon shafts parallel with each other, two propellers, the blades of one ofwhich form a right handed or part of a right handed screw thread, andthe blades of the other a left handed or part of a left handed screwthread of the same pitch as the former and which are placed so closetogether that the blades of one propeller gear into those of the other,so that by rotating the same in opposite directions the mass of waterbetween the two propellers forms a sort of an abutment for the blades towork against, so that the slip of the screws is prevented in a greatmeasure.

To enable others skilled in the art to fully understand and construct myinvention, I will proceed to describe it.

A, represents the stern of a vessel which forms the bearin s for twoparallel shafts B, B, to the ends of which the screw propellers C, C',are attached. The outer ends of the shafts B, B', are supported by aframing D, which is attached to the stern of the vessel in the usualmanner.

The blades c, of the propeller C, form one complete turn of a righthanded screw thread, and the blades c, of the pro eller C, form a lefthanded screw thread o precisely the same pitch as the first one, and theshafts B, B, are so close together that the blades of one propeller gearwith those of the other, as clearly represented in Fig. 2. One of thepropellers may be att-ached to its shaft in such a manner that the samehas some play in a longitudinal direction, so that allforeign-substances, such as pieces of wood or other things floating onthe water, which might get between the two screw propellers, may passfreely between the blades without injuring them.

The two shafts B, B, are connected by gear wheels D, D', and motion iscommunicated to one of the shafts from some motive power. It is,however, not absolutelynecessary to connect the two shafts by these gearwheels, as the friction of one screw against the other is sufficient toconvey motion from one to the other, I would prefer however to connectthe shafts by wheels as it would be injurious to the blades of thepropellers should one of them be propelled merely by the frictionbetween its blades and the blades of the other.

In order to propel the vessel, the screws are rotated in the directionof the arrows, and the mass of water between the blades c of thepropeller C, and the blades c', of the propeller C, forms a sort ofabutment as the blades of one propeller push the water against those ofthe other propeller, so that the screws have considerably more hold onthe water than propellers arranged in the usual way and the vessel ispropelled with a great deal more advantage as a much smaller amount ofthe edective power of the screws is lost by slip.

It is obvious that the action of these propellers is the same in either'direction, so that they act with the same advantage in backing, as theydo in propelling the vessel, it may however be desirable to increase thepropelling power of the vessel and this may be done by giving the bladesa small inclination in the direction from the vessel whereby the wateris thrown more effectually in the space between the blades c, of one andthose c, of the other screw, if the same be rotated in the direction ofthe arrows. In this case however the screws have less power in backingthan in propelling the vessel and where the same power is required inboth cases the blades should be placed on the hubs in an uprightposition.

A particular advantage arising from the use of my propellers is the easewith which the boat is steered as it feels the rudder more sensiblyowing to the current formed by the rotation of the wheels, the rudderbeing directly in the current or where the current leaves the screws.

I do not claim broadly the use of two screws arranged near each other onparallel shafts, for propelling the vessel, but

Having thus described my invention7 what and for the purposes hereinshown and de- I claim as new and desire to secure by Letscribed. tersPatent, is-

The arrangement of the spiral screw pro- DANIEL HUGHES.

5 pellers C, C', so that their blades shall Work Witnesses: nearly inContact and thus present a broad, NELSON SAGE, J unbroken resistingsurface, substantially as FRED. DE LANO.

